* Google's V8 JavaScript engine: This is the most likely meaning if you encountered the term in a programming or web development context. It's a high-performance JavaScript and WebAssembly engine written in C++. It's used in Google Chrome and many other browsers and applications.
* A type of internal combustion engine: In the automotive world, a V8 engine refers to a type of piston engine with eight cylinders arranged in a V-shape configuration. This is typically found in powerful cars, trucks, and boats.
Without more context, it's difficult to say for certain which meaning is intended.